This invention relates to an improved sealing wad or liner for use in closure caps. The invention is particularly suitable for use with ROPP (Roll-On Pilfer Proof) closures and in conjunction with pourers or non-refilling devices fitted inside the bore of a container neck.
A sealing wad or liner is often used in association with known closures. Generally, such closures have a planar crown, to cover the container mouth, and a tubular skirt which depends from the periphery of the crown and is adapted to locate on the outside of the container by, for example, threaded engagement. A sealing wad or liner is received adjacent to the closure crown to provide a seal around the mouth of the container.
For example, FR1378262 describes a plastic disc for use in conjunction with a metal crown. The plastic disc has a projecting annular wall of approximately the same diameter as the internal diameter of a bottle neck and a peripheral lip perpendicular to the disc. As the metal crown is applied to the bottle the lip deforms and seals around the outside of the bottle neck and the annular wall seals against the inside.
In an ROPP closure, a capsule made of thin metal is removably attached to the container. The capsule is fitted in position on the container neck and thread formations are rolled into the capsule skirt, conforming automatically to the underlying threads on the container neck to provided the necessary threaded engagement between the two. At the same time as the thread is formed, the free edge of the skirt is usually rolled inwardly under an annular shoulder on the container. This, in combination with a line of weakening provided around the periphery of the skirt, forms a tamper evident or security band. When the closure is unscrewed for the first time, this band separates from the remainder of the closure along the line of weakening, thereby providing visual evidence that an attempt has been made to open the container.
A waxed, cardboard sealing wad is usually provided in conventional ROPP closures. The sealing wad is retained in the capsule by means of an annular retaining bead formed around the periphery of the closure skirt, adjacent to the crown. When the container is capped, the mouth of the container locally deforms the cardboard sealing wad, to provide a seal. However, cardboard sealing wads are not always suitable, particularly when the container is provided with a device that is designed to be substantially or wholly received in the neck of the container; hereinafter referred to as xe2x80x9cin-borexe2x80x9d, devices. Such devices include, for example, pourers and non-refilling devices for insertion in containers of fine spirits.
Accordingly the present invention provides a closure comprising a closure shell and a liner adapted to seal the mouth of a container, the liner having a sealing flange, arranged to overlie the container mouth, the sealing flange having an upstanding rim around its periphery, characterised in that on application of the closure on the container the upstanding rim folds towards the sealing flange, without folding completely flat, thereby constituting a biasing means for biasing the periphery of the sealing flange against the outside edge of the container mouth.
In particular, the invention provides a means of improving the seal between a closure and a container fitted with an in-bore device, such as a non-refilling device.
Various proposals for in-bore, non-refilling devices are described in Patent Publications U.S. Pat. No. 4,258,854, GB 2026428, WO 96/04179 and WO 98/42587. In U.S. Pat. No. 4,258,854, WO 96/04179 and WO 98/42587, the housing of the non-refilling device is provided with an annular flange which is arranged to overlie the rim of the container. The annular flange acts as a closure liner and provides a seal when the closure is fully tightened onto the container. The annular flange is adapted to releasably engage with the main body of the non-refilling device. Thus, the in-bore device can be assembled inside the closure cap prior to delivery to the bottling line. The combined closure and in-bore device can then be applied to the container neck as a single unit, reducing the time required to cap the bottles.
A disadvantage of this arrangement is that it is difficult to obtain as good a seal as can be achieved using the conventional cardboard wad. This causes particular problems when the filled bottles are being transported or stored in adverse conditions, such as hot and humid conditions. However, use of a conventional cardboard wad in conjunction with a non-refilling device is considered unacceptable as the closure has to be applied to the bottle independently of the in-bore device which increases process times and costs.
Therefore, the present invention also aims to provide an in-bore device, such as a non-refilling device, having the advantages of the existing in-bore devices but with improved sealing performance. The device must be capable integration with the closure or capsule for delivery to the filling line, relatively cheap and easy to mould and easy to assemble, but should seal the container opening as well as a closure containing a conventional cardboard wad.
Accordingly, the present invention also provides an in-bore device for a container having a body portion, at least part of which is adapted to be held firmly in the neck of a container, and a liner portion, arranged to be held captive in a closure and to co-operate releasably with the body portion, the liner portion having a sealing flange, arranged to overlie the container mouth, the sealing flange having an upstanding rim around its periphery, characterised in that on application of the closure and in-bore device to the container the upstanding rim folds towards the sealing flange, without folding completely flat, thereby constituting a biasing means for biasing the periphery of the sealing flange against the outside edge of the container mouth.
The liner according to the invention is preferably made of a plastics material. When used in conjunction with an in-bore device, the liner is provided with means for releasable engagement with the body portion of the in-bore device. This releasable connection may be provided, for example, by a snap fit arrangement or by frangible bridges, which break on first opening of the container. The in-bore device and liner may be inserted into the closure cap and the resultant integrated unit provided to the bottling line for insertion into the neck of a container.
The upstanding rim is located around the periphery of the liner, between the opposed surfaces of the liner and the crown of the closure. As the closure is applied to the container, the force applied to the closure crown by the capping head folds the upstanding rim towards the sealing flange, which in turn forces the periphery of the liner around the outside edge of the mouth of the container, thereby providing a seal. The upstanding rim may be segmented or shaped to provide the required sealing force. Where the closure crown is made from a thin, deformable material, such as in an ROPP closure, the upstanding rim is preferably continuous, to reduce the risk of producing a witness mark on the crown of the closure during the capping process.
The upstanding rim around the periphery of the liner is configured to have a spring characteristic when it is folded. As the closure is applied to the container, the spring bias in the folded structure provides the biasing force required to force the periphery of the liner around the outside edge of the rim of the container. The biasing effect of the liner is not reliant on the inherent resilience of the liner material. Thus, the invention is particularly advantageous where the liner is made from a relatively rigid material due to the need to provide engagement means, so that the liner can be releasably connected to an in-bore device, for example.
On application of the closure to the container, the upstanding rim is folded towards the sealing flange by the force exerted on the crown of the closure by the capping head. In its folded configuration, the rim acts like a folded spring and biases the periphery of the liner around the outside edge of the container mouth. In order to ensure that the folded rim acts like a folded spring rather than a local material thickening, it is important that the rim is not folded completely flat against the sealing flange.
Preferably, a spacer is provided between the opposed surfaces of the crown of the closure and the liner. The spacer may take the form of an upstanding boss, a number of discrete upstanding bosses or an annular ridge. Where the closure crown is made from a thin, deformable material, such as in an ROPP closure, the spacer is preferably a solid boss which extends over substantially the whole surface of the closure crown, in order to reduce the risk of witness marks appearing on the crown.
The spacer preferably defines a cavity into which the upstanding rim can fold. Again this ensures that the liner presents a smooth surface to the closure crown and does not give rise to witness marks on the crown during capping. The spacer may be adapted to prevent the fold, between the rim and the periphery of the sealing flange, from buckling and folding completely flat. If the fold is completely flattened the additional spring bias effect will not be achieved.
The closure liner according to the invention provides an effective seal by wrapping the periphery of the liner around the outside edge of the container mouth. The liner is simple to mould and may be provided with other features, such as engagement tabs for connection of the liner to an in-bore device for example.
The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: